Evidence of magnetism-induced topological protection in the axion insulator candidate EuSn<sub>2</sub>P<sub>2</sub>.

Pierantozzi, Gian Marco; De Vita, Alessandro; Bigi, Chiara; Gui, Xin; Tien, Hung-Ju; Mondal, Debashis; Mazzola, Federico; Fujii, Jun et al. · Proc Natl Acad Sci U S A · 2022

basic_science · Level V

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Abstract

We unravel the interplay of topological properties and the layered (anti)ferromagnetic ordering in EuSn<sub>2</sub>P<sub>2</sub>, using spin and chemical selective electron and X-ray spectroscopies supported by first-principle calculations. We reveal the presence of in-plane long-range ferromagnetic order triggering topological invariants and resulting in the multiple protection of topological Dirac states. We provide clear evidence that layer-dependent spin-momentum locking coexists with ferromagnetism in this material, a cohabitation that promotes EuSn<sub>2</sub>P<sub>2</sub> as a prime candidate axion insulator for topological antiferromagnetic spintronics applications.